Container for recovering used liquids

ABSTRACT

The present invention relates to a container ( 1 ) for collecting waste liquids, comprising a closed tank ( 10 ) of predetermined volume comprising on the top ( 101 ) a pipe ( 14 ) for filling it with waste liquid and a drain pipe ( 15 ) for draining the stored liquid by suction, characterized in that the tank ( 10 ) comprises in the interior a bag ( 102 ), the volume of which is approximately equal to that of the tank ( 10 ), and which is designed to take the waste liquid, a heating system ( 11 ) being attached to the vertical lateral outside walls of the tank ( 10 ) in order, by regulation, to keep the waste liquid stored in the bag ( 102 ) in the tank ( 10 ) at a temperature above its solidification temperature and allow the waste liquid to be drawn off at any time, the tank ( 10 ) being covered with an insulator ( 20 ) and then with a protective casing ( 21 ) to prevent thermal losses, allow the liquid to be heated with little power, and allow storage either indoors or out of doors.

The present invention relates to the field of the management of used liquids such as flammable, petroleum or further food products, and proposes a container for recovering used liquids. More particularly, the invention proposes a container for recovering used oils, notably food oils.

Presently, the problem encountered with the recycling of oil is that there exist different recycling circuits. The first is the animal feed circuit. As oil has a strong caloric value, certain animal feed producers use it in their composition. However, this type of recycling is subject to very strict regulations. Indeed, the quality of the oil should be impeccable. Therefore this requires being certain that the recycled oil has not been polluted by any toxic product unfit for consumption. Indeed, this pollution may also pollute the meat of animals which have eaten the feeds based on polluted oil and therefore endanger the quality of the meat. Thus, in the catering sector, the trend is in fact to set up a traceability system upstream and downstream for used food oil in order to ensure that the oil will not be introduced into the circuit for producing foodstuffs used by catering establishments.

The second circuit is the circuit of technical production. This recycling circuit requires minimum qualities of the oil, notably as regards oleic acidity content.

The oil storing and handling constraints are the following. As a general rule, used oil solidifies or sets at a room temperature of the order of 20° C. to 30° C. depending on the oil used. Its storage is for example accomplished with fully opening barrels to be replaced periodically. But this technique has risks for the personnel and is very restrictive as regards storage and handling. Further, because the oil may set, the transfer of the oil from one container to another may only be carried out at a temperature above the solidification temperature.

For this, document EP 1 180 482 proposes a container for recovering used food oil comprising a closed tank of a determined volume comprising on the top, a discharge conduit by oil suction, an end of the discharge conduit being located in proximity to the bottom of the tank. The tank also comprises in proximity to the bottom, heating means for bringing the oil to a temperature above its solidification temperature. The heating means are switched on by control means at a first determined instant, this first determined instant being selected so that the oil stored in the tank is sufficiently liquid at a second determined instant, selected by the user, so as be able to be drained by suction. But with this type of container, the food oil is in contact with the heating means. Indeed, the used food oil also comprises water and in the presence of a heat source, this water causes fermentation which generates an increase in the oleic acid level. This increase in the oleic acid level makes the used oil difficult to recycle and/or substantially reduces its resale price. Further, the heating of the food oil stored in this container is switched on by the user before it is collected so that the food oil is heated sufficiently rapidly for it to be collected. However, the users tend to forget to switch on the heating of the food oil which imposes that the truck is forced to return once again for collecting it.

The object of the present invention is to overcome one or more drawbacks of the prior art and to propose a container for recovering used food oil with which it is possible to ensure outdoor or indoor storage of the oil without degradation of its properties, autonomous heating of the food oil and allowing discharge of the food oil in the form of a food liquid.

In order to achieve this object, the container for recovering used liquids comprising a closed tank of determined volume comprising on the top a conduit for filling it with used liquid and a discharge conduit by suction of the stored liquid, is characterized in that the tank inside comprises a pocket with a volume substantially equal to the volume of the tank, intended to receive the used liquid, a heating system being attached by adhesion, crimping or adhesive bonding on the outer vertical sidewalls of the tank in order to permanently maintain by regulation, the used liquid stored in the pocket of the tank, at a temperature above its solidification temperature and allowing the used liquid to be collected at any moment, the tank being covered by an insulator and then by a protective tarpaulin for avoiding heat losses, allowing the liquid to be heated with low power and allowing both indoor and outdoor storage, the system including at least one light or visual or sound indicator on the top of the tank (10) in order to warn the operator on the filling state of the pocket (102) of the tank (10) and therefore, to foresee possible collecting of the used liquid by a recovery vehicle.

According to another particularity, the insulator is set into place by a simple lining on the top and on the outer sidewalls of the tank and optionally by adhesive bonding or screw-nut attachment under the container.

According to another particularity, the tank equipped with the heating system and covered by the insulator and the protective tarpaulin is mounted on a transport pallet.

According to another particularity, the container includes a system for detecting the filling level of the pocket of the tank provided on the top of the tank.

According to another particularity, the tank includes a vent notably forming an air intake, the vent being obturated by an anti-odor air filter with which it is possible to suppress or at the very least reduce the diffusion of odors related to the storage of the used liquid in the pocket of the tank or an overflow safety system of the pocket of the tank or an assembly consisting of a funnel with a secured opening (22) and of an anti-odor air filter (16).

According to another particularity, the thickness and the density of the insulator are determined so as to their being sufficient so that the heating system of reduced thickness comprised between 2 mm and 3 mm may maintain with suitably regulated low heating power comprised between 20 W and 200 W, the used liquid at a temperature above its solidification temperature.

According to another particularity, the protective tarpaulin is formed in high tenacity polyester and includes adherence characteristics at least equal to 8 daN/5 cm² according to the NF EN ISO 2411 standard, cold and heat resistance characteristics comprised between −30° C. and 70° C., flame-retardant characteristics of at least equal to 100 mm/min according to the DIN 75 200 standard, breakage resistance at least equal to 220/210 daN according to the NF EN ISO 1421 standard and tear resistance at least equal to 30/25 daN according to the DIN 53363 standard.

According to another particularity, a leak detection system is provided on the top of the tank and includes a float mounted on a vertical rod either equipped with an electronic system generating a signal representative of the liquid level measured by the float or with a mechanical system indicating through a visual indicator the liquid level measured by the float, the float and the vertical rod being positioned in the open space formed by the tank and the pocket so that if the pocket leaks or is broken, the used liquid flows out on the outside of the pocket but in the tank which causes the float to rise again, in the case of an electronic system, the latter generates the signal representative of the liquid level measured by the float so that a visual, light or sound indicator of the leak detection system informs the operator on the leak.

According to another particularity, the inner pocket of the tank of the container is sealably attached to the tank at the filling and discharge conduits, at the anti-odor air filter, at the leak detection system and at the filling level detection system.

According to another particularity, the insulator and the protective tarpaulin are positioned on the container so that they leave clear the filling and discharge conduits, the anti-odor air filter, the leak detection system and the filling level detection system.

According to another particularity, the inner pocket of the tank is in high density polyethylene (HDPE) or in any other materials of the plastic type having flexibility and resistance characteristics or further in a semi-rigid material, is manufactured without any welds in order to avoid its piercing and is insensitive to corrosion.

According to another particularity, the filling conduit and the discharge conduit only form a single conduit both intended for filling and for emptying the pocket of the tank of the container, this filling and discharge conduit being provided on the top of the tank, including an end protruding outside the tank, opening out inside the pocket of the tank and including at its free end a connector capable of receiving both a connector of a flexible or mobile conduit of a pumping device and the connector of a vehicle for collecting or recovering used liquid.

According to another particularity, the filling conduit and the discharge conduit protrude outside the tank of the container, open out into the pocket and are respectively equipped at their free end with a connector, the connector of the filling conduit allowing connection of a flexible or mobile conduit of a pumping device for emptying a mobile container of smaller size than the container and the connector, the interconnection portions of which are with non-standard shapes of the discharge conduit, allowing connection of the pumping conduit of a recovery vehicle equipped with a connector mating the one mounted on the discharge conduit.

According to another particularity, the free end of the filling conduit is equipped with a filtering element with which suspended particles present in the used liquid may be retained.

According to another particularity, the discharge conduit opens out into a boss, with a cylindrical shape, of a diameter greater than the diameter of the discharge conduit or with a hemispherical shape, made in the bottom of the tank and forming a receptacle so that it is positioned at a level located below the bottom of the tank in order to suck up all the liquid stored in the pocket of the tank, except for a small amount substantially corresponding to the volume of the boss minus the sinking depth of the discharge conduit in the boss.

According to another particularity, one of the ends of the discharge conduit comprises a strainer avoiding the suction of waste or debris present in the pocket of the tank.

According to another particularity, the connector of the filling conduit and the connector of the filling and discharge conduit may be equipped with an adaptor so as to be able to receive the neck of a funnel so that an operator may easily pour used liquid contained in a container into the tank.

According to another particularity, the heating system includes heating elements positioned on the external sidewalls of the tank in order to allow by conduction uniform heating of the volume of used liquid stored in the pocket of the tank.

According to another particularity, the heating system is permanently controlled by regulation with a control system positioned on the top of the tank.

According to another particularity, the heating elements of the heating system are coupled with a regulation device, notably comprising a temperature sensor, so that the heating elements are only powered when the temperature of the liquid is below its melting temperature.

According to another particularity, the electric control system comprises at least:

a receiving element intended to receive information relating to the temperature of the used liquid stored in the pocket of the tank, from the regulation device;

a module for processing information relating to temperature of the used liquid; and

an emission element intended to send control instructions for powering the heating system when the temperature of the liquid is below its melting temperature in order to maintain the liquid stored in the pocket of the tank at a temperature above its solidification temperature.

According to another particularity, non-operation indicators are installed on the heating elements of the heating system in order to warn the user that at least one heating element of the heating system is no longer operating.

According to another particularity, the system for detecting the filling level is of the mechanical type such as a gauge and may be replaced by any other electronic or mechanical device indicating a level.

According to another particularity, the tank is in metal and is of a substantially rectangular parallelepipedal shape.

According to another particularity, the metal pallet comprises apertures laid out so as to be able to use a transpallet or a lift truck either in the direction of the length of the tank or in the direction of the width of the tank.

According to another particularity, at least two vertical sidewalls, positioned opposite each other, of the tank are each provided with a handle in order to ensure easy manual handling of the container.

According to another particularity, the dimensions of the tank are selected in order to meet the specific storage need of each user and the periodicity constraints on collecting the used liquid.

According to another particularity, the liquid is food oil, petroleum products, lubricants, hydraulic oils, flammable products.

The invention will be better understood and other objects, characteristics, details and advantages thereof will become more clearly apparent during the explanatory description which follows, made with reference to the appended figures given as non-limiting examples wherein:

FIG. 1 illustrates a diagram of the container for recovering used food oil according to the invention;

FIG. 2 a illustrates a diagram of the container for recovering food oil according to the invention;

FIG. 2 b illustrates a view along the section 2 b-2 b of the container for recovering used food oil;

FIG. 2 c illustrates a view of the element 2 c of the container for recovering used food oil according to the invention.

The invention relates to a container (1) for recovering used food oil allowing outdoor or indoor storage of the oil without degradation of its properties, autonomously heating the food oil and allowing emptying in liquid form of the food oil.

With reference to FIG. 1, the container (1) according to the invention with a substantially rectangular parallelepipedal shape comprises a metal tank (10) with a substantially rectangular parallelepipedal shape which comprises a bottom (100) connected to a top (101) through vertical sidewalls. A heating system (11) is attached on the external vertical sidewalls of the tank (10).

It should be noted that the description refers to a container (1) for recovering used food oil but the tank (10) of the container (1) is also suitable for receiving a determined volume of liquid, such as fuel, gas oil, agricultural gas oil, lubricants, classified liquids, hydraulic or heat transfer oils, or non-combustible oils or further used oils with a flash point above 55° C.

The tank (10) equipped with a heating system (11) is covered by an insulator (20) and then by a protective tarpaulin (21). The tank (10) equipped with the heating system (11) and covered by the insulator (20) and the protective tarpaulin (21) is mounted on a metal pallet (12) allowing the handling of the assembly (10, 11, 20, 21) via conventional lifting devices such as a transpallet or a lift truck. The metal pallet (12) comprises apertures (120) laid out so as to be able to use a transpallet or a lift truck either in the direction of the length of the tank (10) or in the direction of the width of the tank (10).

It should be noted that this device allows both indoor and outdoor storage.

Further, at least two vertical sidewalls, positioned opposite each other, of the tank (10) and the heating device (11) are each provided with a handle (13) for ensuring easy manual handling of the container (1).

The tank (10) is in metal and all the joints of the tank (10) are welded. The dimensions of the tank (10) are selected so as to meet the specific storage need of each user and the periodicity constraints of collecting the food oil.

The tank (10) of the container (1) inside comprises a pocket (102) provided for receiving a determined volume, for example 700 or 1,000 liters of used food oil depending on the amount of food oil consumed by catering establishments, the volume of the pocket (102) being substantially equal to the volume of the metal tank (10).

For example, the tank (10) with a capacity of 700 liters substantially includes a length of 1.1 meters, a width of 0.7 meters and a height of 0.9 meters and the tank (10) with a capacity of 1,000 liters substantially includes a length of 1.1 meters, a width of 0.7 meters and a height of 1.3 meters.

The inner pocket (102) of the tank (10) is in high density polyethylene (HDPE) or in any other materials of the plastic type having flexibility or strength characteristics or further in a semi-rigid material. Advantageously, the inner pocket (102) is manufactured without any welds in order to avoid its piercing and it is insensitive to corrosion unlike the metal tank into which the used food oil was directly poured.

Advantageously, the tank (10) provided with the pocket (102) gives the possibility of meeting the requirements of regulations which impose having a retention pan, for any food liquid, petroleum product or flammable liquid, if the container of said liquid or product is broken.

Additionally and advantageously, the container (1) is provided for catering establishments with low, medium or strong consumption of food oil.

The selection of the value of the width of the tank (10) is determined so as to be able to handle the container (1) in a doorway. Also, the height of the tank (10) is determined so that an operator may observe or easily reach the top of the tank (10). Other dimensions may be selected notably according to the desired storage capacities and to implantation constraints of the container (1) and for obtaining minimum required space for maximum capacity.

A first so-called filling conduit (14) and a second so-called pumping or discharge conduit (15) of the tank (10) are provided on the top (101) of the tank (10). The filling (14) and pumping (15) conduits protrude outside the tank (10) of the container (1), opening out into the pocket (102) and are respectively equipped at their free end with a connector (140, 150).

With the connector (140) of the filling conduit (14) it is possible to connect a flexible or mobile conduit of a pumping device, for example, a manual pump or an electric pump of a transfer system for emptying a mobile container of smaller size than the container (1) according to the invention, the container of smaller dimension being for example removably or fixedly mounted on the transfer system in order to bring the containers of used food oil as close as possible for transferring the oil into the pocket (102) of the tank (10).

The end of the filling conduit (14) may also be equipped with a filtering element with which the suspended particles present in the used food oil may be retained.

The filling conduit (14) of the tank (10) only protrudes on the outside of the tank (10) while the discharge conduit (15) of the tank (10) comprises a first end which opens out on the outside of the tank (10) while protruding and a second end which opens out inside the pocket (102) of the tank (10) in the vicinity of the bottom (100) of the tank (10). The distance between the second end and the bottom (100) of the tank (10) is selected in order to allow suction of the quasi-totality of the food oil stored in the pocket (102) of the tank (10).

According to an alternative embodiment, the second end of the discharge conduit (15) opens out in a boss made in the bottom (100) of the tank (10) and forming a receptacle. The second end of the discharge conduit (15) is then positioned at a level located below the bottom (100) of the tank (10). Consequently, since the pocket (102) substantially follows the geometrical shape of the tank (10), during the emptying of the pocket (102) of the tank (10) by suction, all the oil, except for a small amount substantially corresponding to the volume of the boss minus the sinking depth of the discharge conduit (15) in the boss, is sucked up. Advantageously, with this characteristic, it is then possible to retain a negligible amount of oil stagnating in the bottom (100) of the pocket (102) of the tank (10). Indeed, a too large amount of oil stagnating in the bottom (100) of the pocket (102) of the tank (10) would then generate proliferation of bacteria detrimental to the quality of the used oil which would then be again introduced into the pocket (102) of the tank (10). Also, in order to improve the effectiveness of the pumping, the bottom (100) of the tank (10) may comprise at least one slope, the low portion of which comprises the boss.

According to the alternative embodiment, the boss is for example of a cylindrical shape with a diameter greater than the diameter of the discharge conduit (15). In another alternative embodiment, the boss is hemispherical.

In an alternative embodiment, the second end of the discharge conduit (15) comprises a strainer avoiding suction of waste or debris present in the pocket (102) of the tank (10). Also, the first end of the discharge conduit (15) comprises the connector (150), the interconnection portions of which are non-standard shapes. Thus, only one recovery vehicle equipped with a connector mating the one mounted on the discharge conduit (15) may be connected to the tank (10), with which it is possible to ensure that the intermediate having carried out the connection is a particular intermediate having the adequate connector.

In an alternative embodiment (not shown) of the container (1), a single conduit intended both for filling and for pumping the pocket (102) of the tank (10) of the container (1) is provided on the top (101) of the tank (10). This single conduit includes an end protruding on the outside of the tank (10) and opens out in the interior of the pocket (102) of the tank (10). This single conduit includes at its free end, a connector capable of receiving both the connector of a flexible or mobile conduit of a pumping device and the connector of a vehicle for collecting or recovering the used food oil.

It should be noted that the connector (140) of the filling conduit (14) and in the case of the alternative embodiment described above, the connector of the filling and discharge conduit may be equipped with an adaptor allowing the receiving of the neck of a funnel so that an operator may easily pour the used food oil contained in a container into the tank (10).

The top of the tank (10) also comprises a vent notably forming an air intake. This vent may be obturated by an anti-odor air filter (16) allowing suppression, or at the very least reduction, in the diffusion of odors related to the storage of the used food oil in the pocket (102) of the tank (10) or of an overflow safety system of the pocket (102) of the tank (10).

Also, a funnel with a secured aperture (22) may be attached between said vent and the particle filter (16). The presence of this funnel (22) with a secured aperture allows an authorized user to have a secondary effective means for filling the container with used oil.

According to the invention, the container (1) also comprises the heating system (11) including heating elements, for example a heating plate, attached on the external vertical sidewalls of the tank (10). This heating system (11) is not in contact with the used food oil stored in the pocket (102) of the tank (10) since the heating system (11) is positioned on the tank (10). This heating system (11) allows by conduction, uniform heating of the volume of used food oil stored in the pocket (102) of the tank (10).

This heating system (11) is permanently controlled and regulated by a control system (17), further called an electric servocontrol box, positioned for example on the top (100) of the tank (10).

The essential function of the heating system (11) is to permanently provide a sufficient amount of heat energy for liquefying the whole used food oil stored in the pocket (102) of the tank (10) in order to allow at any moment collection of the used food oil stored in the container (1). Therefore, the heating system (11) should permanently maintain the food oil at a temperature above the solidification temperature which is of the order of 30° C.

In an alternative embodiment, non-operation indicators are installed on the heating elements of the heating system (11). These indicators may be light or sound indicators and installed on a visible surface of the container (1). Thus, as soon as at least one heating element is no longer operating, the operator is warned and may then ask for the replacement of the faulty heating element. Thus the benefit of placing at least one assembly of at least two heating elements inside the heating system box (1) is that it is very unlikely that all the heating elements will be faulty at the same time. Therefore it will always be possible to liquefy the whole food oil present in the pocket (102) of the tank (10) and to empty the pocket (102) of the tank (10) while awaiting replacement of the faulty heating element.

The heating elements of the heating system (11) are coupled with a regulation device (not shown), notably comprising a temperature sensor, so that the heating elements are only powered when the temperature of the food oil is less than the melting temperature, increased for example by 15° C., with a deviation of ±5° C. Thus, if the melting temperature of the used food oil is 25° C., the heating elements will no longer be powered as soon as the temperature of the oil is no longer comprised in the interval 35° C.-45° C. In this way, since the oil is permanently liquid, the emptying of the pocket (102) of the tank (10) is possible at any moment.

In a non-limiting way, the heating elements are for example of the DYNAFLEX type.

The electric control system (17) comprises at least:

one receiving element intended to receive information relating to the temperature of the used food oil stored in the pocket (102) of the tank (10) from the regulation device;

one module for processing the information related to the temperature of the used food oil; and

one emission element intended to send control instructions for powering the heating system (11) when the temperature of the food oil is less than the melting temperature in order to maintain the used food oil stored in the pocket (102) of the tank (10) at a temperature above the solidification temperature.

Further, the container (1) is equipped with a system for detecting the filling level (18) of the pocket (102) of the tank (10). The light or visual or further sound indicator of the filling level detection system (18) is positioned on the top of the tank (10) in order to allow the operator to be informed on the filling state of the pocket (102) of the tank (10) and therefore to foresee a possible collection of the used food oil by a recovery vehicle. In a non-limiting way, the system for detecting the filling level (18) is of the mechanical type such as a gauge and may be replaced with any other mechanical or electronic device for indicating a level.

The container (1) is also equipped with a leak detection system (19) which consists of a float mounted on a vertical rod which is equipped with an electronic system generating a signal representative of the oil level measured by the float or with a mechanical system indicating via a visual indicator the liquid level measured by the float. The float and the vertical rod are positioned in the open space formed by the tank (10) and the pocket (102) so that the float is positioned in proximity to the bottom (100) of the tank (10) and between the tank (10) and the pocket (102). If the pocket (102) leaks or is broken, the used food oil flows on the outside of the pocket (102) but into the tank (10) which causes the float to move up again. In the case of an electronic system, the latter generates the signal representative of the oil level measured by the float so that a visual, light or sound indicator of the leak detection system (19) informs the operator on the leak. This visual, light or sound indicator of the leak detection system (19) is for example positioned on the top (101) of the tank (10).

The insulator (20) is set into place by lining, by adhesive bonding or by attachment elements of the screw-nut type on the top (101) and on the outer sidewalls of the tank (10) and optionally under the container (1). In a non-limiting way, this insulator is for example of the Airflex type.

The thickness and the density of the insulator (20) are determined so as be sufficient so that the heating system (11) of reduced size may maintain with suitably regulated low heating power, the food oil at a temperature above the solidification temperature. In a non-limiting way, the heating system has reduced thickness which is advantageously comprised between 2 mm and 3 mm.

In a non-limiting way, the insulator has a thickness comprised between 5 mm and 20 mm.

In a non-limiting way, the insulator has a density comprised between 200 g/m² and 1,000 g/m².

In an exemplary embodiment, the thickness of the insulator (20) of 10 mm has a density of 615 g/m² with which the used food oil may be maintained stored in a pocket (102) of a tank (10) with a capacity of 700 liters, at a temperature above the solidification temperature with a heating power comprised between 20 W and 200 W. Advantageously, the heating power is equal to 57 Watts.

Advantageously, the insulator (20) groups the particular characteristics entering the scope of French Standards and meets the requirements of safety and health standards.

Advantageously, the mechanical strength of the insulator is equal to 300 kg/m².

Advantageously, the insulator is located in the fire resistance class M1 according to the NF P. 92.507 standard.

The top surface (101) and the vertical sidewalls of the tank (10) covered with the insulator (20) are then covered with the protective tarpaulin (21). In a non-limiting way, this protective tarpaulin (21) is of the type of the ones used for truck roofs, for the field of agriculture, for screen-printing or further awnings of boats. This protective tarpaulin (21) consists for example in high tenacity polyester and includes adherence, cold and heat resistance characteristics comprised in a non-limiting way between −30° C. and 70° C., fire-retardant characteristics and breakage and tear resistance.

The fire-retardant characteristic is equal to at least, in a non-limiting way, 100 mm/min according to the DIN 75 200 standard.

The adherence characteristic is equal to at least, in a non-limiting way, 8 daN/5 cm² according to the NF EN ISO 2411 standard.

The tear (warp/weft) resistance is equal to at least in a non-limiting way, 220/2101 daN according to the NF EN ISO 1421 standard.

The tear (warp/weft) resistance is equal to at least in a non-limiting way, 30/25 daN according to the DIN 53363 standard.

In a non-limiting way, the tarpaulin has a density equal to 680 g/m².

It should be noted that the inner pocket (102) of the tank (10) of the container (1) is sealably attached to the tank (10) at the filling and discharge conduits (14, 15), at the anti-odor air-filter (16), at the leak detection system (19) and at the filling level detection system (18).

Further, the insulator (20) and the protective tarpaulin (21) are positioned on the container (1) as described earlier so that they leave clear the filling and discharge conduits (14, 15), the anti-odor air-filter (16), the leak detection system (19) and the filling level detection system (18).

One of the advantages of the invention is that the container (1) for recovering used food oil allows the used food oil to be permanently maintained at a temperature above the solidification temperature with a simple application, at a low cost (the number of elements forming the container (1) is reduced) and by limiting the number of failures of the container (1).

It should be obvious for the person skilled in the art that the present invention allows embodiments under many other specific forms without departing from the field of application of the invention as claimed. Therefore, the present embodiment should be considered as an illustration, but may be modified within the field defined by the scope of the appended claims, and the invention should not be limited to the details given above. 

1. A container for recovering used liquids comprising a closed tank of a determined volume comprising on the top a conduit for filling it with a used liquid and a discharge conduit by suction of the stored liquid, wherein the tank comprises in the interior a pocket of a volume substantially equal to the volume of the tank, intended to receive the used liquid, a heating system being attached onto the external vertical sidewalls of the tank and configured to maintain by regulation the used liquid stored in the pocket of the tank at a temperature above its solidification temperature and allow the used liquid to be collected at any moment, the tank being covered by an insulator and then by a protective tarpaulin in order to avoid heat losses, allowing the liquid to be heated with low power and to be stored both indoors and outdoors, the system including at least one light or visual or sound indicator on the top of the tank in order to warn the operator on the filling state of the pocket of the tank and therefore to foresee possible collection of the used liquid by a recovery vehicle.
 2. The container according to claim 1, wherein the insulator is set into place by simple lining or adhesive bonding or by attachment elements of the screw-nut type on the top and on the outer sidewalls of the tank and optionally under the container.
 3. The container according to claim 1, wherein the tank equipped with the heating system and covered by the insulator and the protective tarpaulin is mounted on a transport pallet.
 4. The container according to claim 1, wherein the container includes a system for detecting the filling level of the pocket of the tank, provided on the top of the tank.
 5. The container according to claim 1, wherein the tank includes a vent notably forming an air intake, the vent being obturated by an anti-odor air-filter allowing suppression or at the very least reduction in the diffusion of odors related to the storage of the used liquid in the pocket of the tank or of an overflow safety system of the pocket of the tank or of an assembly consisting of a funnel with a secured aperture and of an anti-odor air-filter.
 6. The container according to claim 1, wherein the thickness and the density of the insulator are determined so as to be sufficient so that the heating system of reduced thickness comprised between 2 mm and 3 mm is configured to maintain, with suitably regulated low heating power comprised between 20 W and 200 W, the used liquid at a temperature above its solidification temperature.
 7. The container according to claim 1, wherein the protective tarpaulin is formed in high tenacity polyester and includes adherence characteristics at least equal to 8 daN/5 cm² according to the NF EN ISO 2411 standard, cold and heat resistance characteristics comprised between −30° C. and 70° C., flame-retardant characteristics at least equal to 100 mm/min according to the DIN 75 200 standard, breakage strength at least equal to 220/210 daN according to the NF EN ISO 1421 standard and tear resistance at least equal to 30/25 daN according to the DIN 53363 standard.
 8. The container according to claim 1, wherein a leak detection system is provided on the top of the tank and includes a float mounted on a vertical rod either equipped with an electronic system generating a signal representative of the liquid level measured by the float, or with a mechanical system indicating by a visual indicator the liquid level measured by the float, the float and the vertical rod being positioned in the open space formed by the tank and the pocket so that if the pocket leaks or is broken, the used liquid flows outside the pocket but into the tank which causes the float to move up again, in the case of an electronic system, the latter generates the signal representative of the liquid level measured by the float so that a visual, light or sound indicator of the leak detection system informs the operator on the leak.
 9. The container according to claim 1, wherein the inner pocket of the tank of the container is sealably attached to the tank at the filling and discharge conduits, at the anti-odor air-filter, at the leak detection system and at the filling level detection system.
 10. The container according to claim 1, wherein the insulator and the protective tarpaulin are positioned on the container so that they leave clear the filling and discharge conduits, the anti-odor air-filter, the leak detection system and the filling level detecting system.
 11. The container according to claim 1, wherein the inner pocket of the tank is in high density polyethylene (HDPE) or in any other materials of the plastic type having flexibility and resistance characteristics or further in semi-rigid material, is manufactured without any welds in order to avoid that it becomes pierced and is insensitive to corrosion.
 12. The container according to claim 1, wherein the filling conduit and the discharge conduit form a single conduit both intended for filling and for emptying the pocket of the tank of the container, the filling and discharge conduit being provided on the top of the tank, including an end protruding on the outside of the tank, opening out inside the pocket of the tank and including at its free end a connector capable of receiving both the connector of a flexible or mobile conduit of a pumping device and the connector of a vehicle for collecting or recovering used liquid.
 13. The container according to claim 1, wherein the filling conduit and the discharge conduit protrude outside the tank of the container, open out into the pocket and are respectively equipped at their free end with a connector, the connector of the filling conduit allowing connection of a flexible or mobile conduit of a pumping device in order to empty a mobile container of smaller size than the container and the connector, the interconnection portions of which are non-standard forms of the discharge conduit, allowing connection of the pumping conduit of a recovery vehicle equipped with a connector mating the one mounted on the discharge conduit.
 14. The container according to claim 13, wherein the free end of the filling conduit is equipped with a filtering member allowing retention of the suspended particles present in the used liquid.
 15. The container according to claim 13, wherein the discharge conduit opens out into a boss, of cylindrical shape with a diameter greater than the diameter of the discharge conduit or of hemispherical shape, made in the bottom of the tank and forming a receptacle so that it is positioned at a level located below the bottom of the tank in order to suck up all the liquid stored in the pocket of the tank, except for a small amount substantially corresponding to the volume of the boss minus the sinking depth of the discharge conduit in the boss.
 16. The container according to claim 13, wherein one of the ends of the discharge conduit comprises a strainer avoiding suction of waste or debris present in the pocket of the tank.
 17. The container according to claim 12, wherein the connector of the filling conduit and the connector of the filling and discharge conduit are equipped with an adaptor with which the neck of a funnel is received so that an operator may easily pour used liquid contained in a container into the tank.
 18. The container according to claim 1, wherein the heating system includes heating elements positioned on the external sidewalls of the tank and configured to uniformly heat the volume of the used liquid stored in the pocket of the tank.
 19. The container according to claim 1, wherein the heating system is controlled and regulated by a control system located on the top of the tank.
 20. The container according to claim 18, wherein the heating elements of the heating system are coupled with a regulation device, notably comprising a temperature sensor, so that the heating elements are only powered when the temperature of the liquid is less than its melting temperature.
 21. The container according to claim 19, wherein the electric control system comprises at least: one receiving element intended to receive information relating to the temperature of the used liquid stored in the pocket of the tank from the regulation device; one module for processing information relating to the temperature of the used liquid; and one emission element intended to send control instructions for powering the heating system when the temperature of the liquid is less than its melting temperature in order to maintain the liquid stored in the pocket of the tank at a temperature above its solidification temperature.
 22. The container according to claim 18, wherein non-operation indicators are installed on the heating elements of the heating system in order to warn the user that at least one heating element of the heating system is no longer operating.
 23. The container according to claim 4, wherein the filling level detection system is of the mechanical type such as a gauge and may be replaced by another mechanical or electronic device for indicating a level.
 24. The container according to claim 1, wherein the tank is metal and has a substantially rectangular parallelepipedal shape.
 25. The container according to claim 4, wherein the pallet in metal comprises apertures laid out in order to use a transpallet or a lift truck either in the direction of the length of the tank or in the direction of the width of the tank.
 26. The container according to claim 1, wherein at least two vertical sidewalls, positioned opposite to each other, of the tank are each provided with a handle in order to ensure easy manual handling of the container.
 27. The container according to claim 1, wherein the liquid is food oil, petroleum products, lubricants, hydraulic oils, flammable products. 